Recollection and conservation of Vatica javanica subsp. scaphifolia, a critically endangered endemic tree species in Southeastern Borneo

Abstract

Vatica javanica subsp. scaphifolia (Kosterm.) P.S.Ashton (Dipterocarpaceae) is an endemic tree confined to Southeastern Borneo. The International Union for Conservation of Nature (IUCN) Red List classifies the species as Critically Endangered (CR) based on the assessment conducted 25 years ago. The species is not collected yet in any ex-situ conservation areas in the world. After more than 3 decades since the last herbarium specimen was collected in 1991, here this study reported the recollection and new locations of V. javanica subsp. scaphifolia in Bukit Bangkirai Forest, Kutai Kartanegara Regency, East Kalimantan Province. The confirmation of the species involved a comparison between the newest collected specimens and living photos and the specimen type and key to the species in the protologue. The present research provides new information on the morphology of the tree species through photos of the wild living plants. Using an exploration survey method, this research recorded the population in two locations with elevation ranges of 70-95 m. The field survey located a total of 13 immature individuals with height and diameter ranges of 2.1-14.7 m and 1-9.7 cm, respectively. The study observed that forest conversion into rubber plantations (Hevea brasiliensis) and open coal mining are the main threats to the species. Conservation of the species has been done by collecting plant materials to serve as the first ex-situ living collection at the Bogor Botanic Gardens BRIN.